Non-invasive microelectrode cadmium flux measurements reveal the decrease of cadmium uptake by zinc supply in pakchoi root (Brassica chinensis L.).

Abstract Zinc (Zn) possesses similar properties to cadmium (Cd) and inhibits Cd uptake in plants. To get more detailed mechanisms of Zn-inhibited Cd uptake in pakchoi, a hydroponic experiment was conducted to investigate the effects of various Zn levels on Cd concentrations, real time flux of Cd, expressions of genes related to Cd uptake under Cd exposure. The results showed that the Cd concentrations and Cd accumulations in pakchoi root decreased with increasing Zn levels, which were coincident with that real time Cd influx and net Cd influx of pakchoi root decreased with increasing Zn levels by non-invasive micro-test technology (NMT). Additionally, the expressions of Cd-related transporters including BcNRAMP5 , BcIRT1 and BcMGT1 decreased with the increase of Zn levels under Cd exposure, especially BcIRT1 with the highest decreased rates. Furthermore, the expressions of these genes decreased gradually with the prolongation of Zn treated time under Cd toxicity. The results indicate that Zn inhibits Cd uptake by inhibition of the expressions of Cd-related transporters, especially BcIRT1 in pakchoi root. Highlights • NMT showed that Zn inhibited net Cd²⁺ influx in root. • Zn reduced Cd uptake by inhibiting expressions of Cd transporter in root. • Zn-reduced Cd uptake was involved in Zn-alleviated Cd toxicity in shoot. [ABSTRACT FROM AUTHOR]